Shaping of sheet metal by fluid pressure



Sept. 25 1923.

T. M. HARRISON SHARING oF SHEET METAL BY FLUID PRESSURE 2 sheets-sheet 1 Filed July 10. 1922 Sept. 25 1923.

T. M.`HARRI$ON SHAPING oF SHEET METAL BY FLUID PRESSURE' 1922 2 Sheets-Sheet 2 Filed July 10 22 .fo 24.5?.5 J2

In. W

Patented sept. 25, 192s.

UNITED STATES y 1,468,706 PATENT orifice.

THEODOBE M. HARRISON, F HAWTHORN, MELBQURNE, VICTORIA, AUSTRALIA, AS- SIGNOB T0 HYDRO PRESS COMPANY PROPBIETABY LIMITED, 0F MELBOURNE, VIC- TORIA, AUSTRALIA.

sHAPING ci SHEET METAL BY 'FLUID PRESSURE.

appi'etien mea. Juiyio, 1922. serial No. 573,829.

To 'all 'wwm z't mary concern:

Be it known that I, THEonoRE MARFLEET Melbourne, in the county of Bourke, State of Victoria, Commonwealth of Australia, have invented certain new and useful Improvements Relating to the Shapin of Sheet Metal by Fluid Pressure, of whic the following is a specification.

This invention relates .to the shaping of sheet. lmetal by lluid pressure and more particularly -to apparatus of the type described in my prior United States Patent No. 1,329,969, dated 3rd February, 1920, wherein preferably hydraulic pressure is admitted to an expansible pressure fluid con` tainer the 'expansion of which causes the sheet metal to be forced into a shaping chamber or cavity of the contour to be imparted tothe metal. The shaping chamber or cavit is formed in an upper or shaping block w ich is capable of being raised, or lowered in relation to a lower block or base, on which the expansible pressure fluid container is disposed, the marginal part of thesheet metal being yieldingly gripped between the two blocks in such manner that the metal is permitted to creep or slip inwardly to a certain extent to take the shapeof the shaping chamber when the pressure is admitted.

In apparatus of the foregoing type it has been the ractise to employ a closed bag of rubber or ike suitable material as the expansible fluid container. It is found that with such a bag thev continual stretching or strain entailed by repeated expansion and contraction of the container under high pressure, causes it to soon become worn and ruptured, particularly at certain points such as the sides of the bag. This necessi tates fre uent renewal of the bag or container, w ich is an expensive item of the installation.

The primary object of the present invention -is to provide an expansible bag or fluid container which may be continually expanded under high -pressure without undue strain on the material of which the bag or container is formed, thereby greatly prolonging the life of the bag and materially reducing the cost of operation. f

Referring to the drawings which form part of this specification Figure 1`is a part sectional side elevation of an apparatus of the kind referred to and to which the present invention. relates; in the exam le illustrated the apparatus is applied to t e shaping of a sheet metal corner panel for automobile bodies, and the upper or shaping block is shown in its raised posi- Figure 2 is a plan of the lower block and the parts resting thereon and showing the improved expansible bag or pressure fluid container.

Figure 3 is an enlarged cross sectional view of the improved expansible bag o r lluid container.

Figure 4 is a part sectional end view of Figure 1, the upper block being lowered and a sheet of metal shown in position to be shaped. The expansible bag is in a collapsed state.

Figure `5 is across sectional view of the lower portion of Figure 4 b'ut showing the expansible ba expanded and the sheet of metal forced into the shaping chamber by the fluid pressure. i v

On reference to the drawings it will be seen that the numerals 2 and 3 indicate' fast and loose pulleys on a pulley shaft 4. The shaft 4 carries a bevel pinion 6 which drives a bevel wheel 7 on a worm shaft 8. A worm 9 on said worm shaft engages a worm Wheel 11 fixed on a main shaft 12 which is thus rovided with a slow and powerful drive.

he shaft 12 turns in bearings in head pieces 13, which are supported by guides 14 upstanding from a base or foundation 15. Keyed to the shaft 12 are eccentrics 16 or cranks, to each of which is attached the upper end of a connecting rod 17 which is capable of easy adjustment by right and left hand screw threads 18 and turning holes 19 or other suitable means in order that it may be extended or shortened as desired. The lower end of each connecting rod is pivoted to and supports a pin 20 carried by a frame 30 secured to an up er or shaping block 25 which moves along t e guides 14'. If desired any suitable mechanism may be provided to automatically throw the eccentric or crank gear out of operation as the block 25 reaches the upper and lower limits of its travel.

The underneath or gripping surface 21 conform to the shape that the border of the sheet metal is to acquire. Inside the border of the shapingeblock is formed a shaping rer 22. The area, height and `A cess or cham conformation of this recess or chamber determine the shape to be imparted to the sheet metal. Into said chamber the metal is upwardly forced and shaped by hydraulic or iiuidl ressure as hereinafter described.

Pre erably there is formed on the underneath surface of the upper block and surrounding'said chamber a depending lip 23. This lip conforms to the marginal shape of said chamber and its inner edge or corner 24 which forms the marginal edge or corner of the chamber is formed square as shown. This square corner of the shaping chamber in contradistinction to a rounded corner forms a material feature of the invention as it causes the marginal portion of the sheet metal to be thoroughly ironed or smoothed out asit is drawn inwardly by the hydraulic pressure. Y

Beneath the .shaping block is a lower block 26. This block rests 'upon the base or foundation 15 and may, if desired, be capable of being moved to a slightl degree either laterally or longitudinally in order that it may be readily aligned with the upper block. The upper surface 27 of the lower block may also be longitudinally curved to conform to the border surface 21 of the shaping block as shown.

Outside the lower block and situated in any suitable position is a valve 29 controlling a water inlet pipe 31 which communicates with a water passageway 32 leading to the centre of the upper surface of the lower block.

A drain pipe 33 also communicates with said water passagewa and is fitted with a pressure gauge 34 an a discharge valve 36 for the purpose of draining the apparatus when the sheet metal has been shaped.

In combination with the foregoing allexible presswatercontainer of stout rubber, canvas or like elastic or flexible material is employed. This container is preferably in the form of a bag 37 which is closed on all sides and is provided at its bottom with an orifice 49 to accommodate a water inlet nipple 39 which is screwed or otherwise connected to the water passageway 32 of the lower block as seen in Figure 2. The marginal edges of the bag lie within the border of the chamber 22 in the upper block.

- According to the present lnvention there is formed, preferably in the top of the bag 37 an opening 50 of comparatively large size,vthis opening may be o elliptical circular, or other suitable conformation and passes right through the wall of the bag as in Figure 3. Covering the opening 50 and 'restinvon top of the baor is an outer flap 51 of ruliher or other suitagle exible' material. This flap is considerably lar of the opening 50 so t at t e iiap overlaps the edge of the opening for some distance. lso extending across said opening and inside the bag is an inner flap 52 of suitable flexible material. This isalso larger than the size of the opening 50 and is otherwisesimilar to the outer flap except that the inner flap is preferably smaller than the outer r than the size fiap so that it may be readily introducedA into and withdrawn from the bag. Said in ner and outer laps are united by .an inter.-

mediate bridge or connecting portion 53 which passes freely through the opening 50 and may be integral with or secured to the aps by metal fasteners 54 or other convenient means. The edges of the flaps are referably bevelled or skived as at 60 to orm an effective water seal around said edges and to prevent the formation of ridges in the sheet metal whenV the fluid pressure is admitted to the bag.

The flaps and bridge or connecting portion 53 constructed as above described, form a flexible closure for the opening 50, the portion of the bag surrounding` said opening eing thus freely accommodated in the annular or like space formed between the outer and inner flaps so that when pressure is admitted to the bag said'portion of the bag is permitted to slip outwardly between the two flaps. This enlarges or distorts the opening 50 and permits the bag to expand without excessive strainv on the material of which it is formed.

In conjunction with the foregoin there is preferably formed around the fluid inlet orifice 49 in the bottom of the bag, an upcal surface 56. Said collar may be formed integral with or attached to the bag and owing to its conical surface 56, the collar is pressed tightly against the nipple 39 to form a liquid tight jolnt around the same when the pressure water is admitted'.

The elastic or flexible bag ma rest on a protecting sheet 41 of rubber, fa ric or like material which lies on the upper surface of the lower block and has its edges turned up over the sides of the bag as at 42 to rotect the latter from injury. A hole is ormcd through the centre of this sheet to pass the ni ple 39 leading to the bag.

esting on the upper surface of the lower block is a rubber or like iexible pad or cushion 44. The inner edge 43 of this cushion conforms to the marginal shape of the chamber in the upper block and surrounds the elastic bag above mentioned.

Resting upon said cushion is a metal iron- -ing frame 46 on which the metal sheet 45 to be treated is placed'. The upper or gripping surface 40'of this frame conforms to the shape or curvature of the surface 21. The inner edge of said frame is provided with a square corner 47 and conforms precisely to the square marginal edge 24 of the chamber in the upper block beneath which edge it is disposed. The ironing frame 4G is held in position by tongues 48 or other` suitable means attached to the lower block. It will be seen that the cushion 44 forms a resilient bed for the ironing frame 46 thereby allowing said frame to yield slightlv in a downward direction and permit the metal sheet 45 to creep inwardly between the ironingframe and the upper block when the hydraulic pressure is applied. If desired the ironing frame' and the cushion 44 as shown may be omitted and a similar result obtained by placing a rubber or like cushion above the upper block 25 (for instance. between said block and the frame 30) or between the lower block 26 and the base 15. This permits of a relative yielding movement between the opposed gripping surfaces formed by the upper and lower blocks so that 'the metal sheet may slip or creep inwardly between the blocks when the fluid pressure is applied.

In operation the sheet metal may first be greased or lubricated and is then placed on top of the bag 37 and between the two blocks 25, 26, the upper block in which the shaping recess or cavity 22 is formed being then lowered on to the metal sheet, the marginal portion of which is gripped between the upper and lower blocks. The cranks or eccentrics being now in their lower dead centre position, the upper block is positively held against upward movement when the pressure fiuid is admitted. By adjusting the length of the connecting rods with the means provided, the grip on the metal sheet 45 may be regulated and different thick" nesses of metal accommodated. Pressure water or fiuid is now admitted to the bag 37 causing it to expand and force the sheet metal into the shaping cavity 22 of the upper block. As the pressure in the bag increases the portion of the bag surrounding the opening 50 thereof slips outwardlyY between the inner and outer flaps thereby enlarging the opening and permitting the bag to expand freely without unduly straining the material of which it is formed. The increasing pressure Within the bag also automatically forms a seal around the opening 50 by pressing the outer surface of the inner flap against the inner surface of the bag, and the outer surface of the bag against the inner surface of the outer flap. A relatively small quantity of the water may escape from the bag through said opening but this does not detrimentally affect thcv sha-ping` operation. The aperture 49 is also sealed around the nipple 39 by the pressure of the fluid against the conical surface 56 as aforesaid. The pressure water is thus retained ter escapes from the bag through the passage 32 and drain pipe 33 and the opening 50 in the bag which thus reassumes its normal state. The upper block is then' raised and the shaped metal sheet removed whereupon thel outturned marginal portion or flange may be severed from the shaped portion by any suitable cutters or the like.

It has been found that in the shaping of 'small articles such as domestic dishes and the like the flexibleclosure formed by the parts 51, 52 and 53 may in some cases be dispensed with,`the edge of the opening 50 being forced outwardly against the sheet metal by the fiuid pressure so that the escape of the water to any material extent through said opening is prevented.

By the invention the strain on the bag through repeated expansion and contraction, is greatlyreduced and the life of the bag .thus extended indefinitely. Working costs are thereby reduced to a minimum resulting in the economical production on a commercial scale andl in a single shaping operation, of various sheet metal articles such for instance as mudguards and corner panels for automobile bodies, dishes, pans, basins and the like.

I claim 1. In apparatus for'shaping sheet metal by fiuid pressure, an expansible bag into which the pressure fluid is admitted to impart the desired shape to theA sheet metal, said bag having an opening through its wall and a fiexible closure freely associated with said. opening, said closure including a flap which overlaps the edge of the opening for the purpose set forth.

2. In apparatus for shaping sheet metall by fluid pressure, an expansible bag into which the pressure fluid is admitted to impart the desired shape tothe sheet metal, said bag havin an opening through its wall and a flexile closure freely associated with said opening, said closure including an inner flap disposed within the bag andJ an outer flap located outside the bag, both of said flaps overlapping the edge of said opening so that the portion of the bag surrounding the opening is freely disposed between the flaps for the purpose set forth.

3. In apparatus for shaping sheet metal by fluid pressure, an expansible bag into which the pressure fluid is admitted to impart the desired. shape to the sheet metal, said bag having an openin through its wall and a flexible closure free y associated with said opening, said closure including an inner flap disposed within the bag and an outer flap located outside the bag, both of said fiaps overlapping the edge of 'said opening,

and a bridge or connecting portion extending between the flaps and paing'freely through said opening whereby the portion of the bag surrounding said opening is freely disposed between said flaps for the purpose Vsaid flaps overlapping the edge of said opening, and a bridge or connecting portion extending between the flaps and passing freely through said opening-whereby the portion of the bag surroundin said opening is freely disposed between said flaps, said bridge or connecting portion being formed separately from the flaps and secured thereto by fasteners which pass through the two flaps and the connecting portion. A

5. In Aapparatus for shaping sheet metal by fluid pressure, an expans1ble bag: into which the pressure fluid is admitted to impart the desired shape to the sheet metal, said bag having an opening through its wall and a flexible closure freely associated with said opening,gsad closure including a flap which overlaps the edge of the openmg, said bag having an additional aperture formed through its wall to accommodate a fluid inlet ni ple or tube and. a flexible collar surroundli) ng said aperture and projecting inwardly into the ba said collar having a conical surface fort e purpose s ecified.

'6. In apparatus for shapin s eet metal by fluid pressure, an expansilble bagv into which the pressure fluid is admitted to impart the desired shape to the Vsheet metal, said bag having an opening through its wall and a flexible closure freely associated with said opening, said closure including a ila which ov `rlaps the edge of the opening an is provided with a beveled edge, substan-i tially as described.

7. An improved apparatus for shaping sheet metal by fluid pressure, comprising in combination a pair of opposed blocks disposed one above the other, one of said blocks aving a shaping cavity therein, means for relatively moving said blocks towards and from each other to respectively. ,ri and release the marginal portion o t e metal sheet, cushioning means to permit relative Ayielding movement between ythe blocks ture.

THEO. M. HARRISON. Witness:

CECIL MCCLASTREN. 

